JPH06111384A - How to duplicate stamper for optical disk - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a stamper duplication method for an optical disk, which does not require waste liquid treatment, has no environmental problems, does not contaminate an electroplating solution, and has a high transferability and few defects. . [Structure] A stamper having release films 1a and 2a made of an oxide film formed by oxygen plasma ashing is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reproducing a stamper used for manufacturing an optical disc.

[0002]

2. Description of the Related Art A conventional method for manufacturing an optical disk stamper and a method for copying the same will be described with reference to FIG. After cleaning the optically polished glass plate 11 (FIG. 3A), a photoresist film 11b (having a thickness of 150) is formed on the glass plate 11.
(about nm) is applied (FIG. 3B). The photoresist is exposed by irradiating laser light modulated according to the signal to be recorded. The exposed portion is developed and removed to form fine irregularities (FIG. 3C), and the conductive film 12a necessary for electroplating is attached to the surface of the glass master 12 (FIG. 3D). Usually, the conductive film is made of Ag or Ni and is applied by the sputtering method or the electroless plating method. After that, nickel electroforming is performed using this as an electrode, and the glass master is peeled off to obtain a master stamper 13 (hereinafter, the stamper used to duplicate the stamper is referred to as a master stamper) (FIG. 3).
(E), (f)). When the master stamper 13 is used to duplicate an optical disk stamper, the surface of the master stamper 13 is cleaned by electrolytic degreasing, and then the release coating 13a is formed on the master stamper (FIG. 3).
(G)). Further, nickel electroforming is performed using the master stamper 13 as an electrode, nickel is attached to a predetermined thickness, and then peeled off to form a mother stamper 14 (hereinafter,
A stamper duplicated from the master stamper is called a mother stamper. ) Is obtained (FIG. 3 (h)). After the surface of the mother stamper 14 is washed by the electrolytic degreasing method, the release coating 14a is formed on the mother stamper 14. When nickel electroforming is performed using this mother stamper 14 as an electrode, a sun stamper 15 (hereinafter, a stamper duplicated from the mother stamper is referred to as a sun stamper) having the same concavo-convex pattern as the master stamper 13 is obtained (FIG.
1)). In the duplication process of the stamper for an optical disc, a chromium oxide film formed by using a dichromic acid solution is generally used as the release coatings 13a and 14a.

[0003]

In the conventional method of forming a release coating on the surface of a stamper for an optical disk with a dichromic acid solution, the dichromic acid solution used is a pollutant, so the waste liquid may be discarded as it is. However, there is a problem that it is difficult to use the dichromic acid solution due to the fact that it is necessary to carry out some kind of waste liquid treatment, the cost of waste liquid treatment is high, and the tightening of regulations concerning environmental problems makes it difficult to use the dichromic acid solution. In addition, the dichromic acid solution has a drawback in that the electroplating solution is severely fatigued and contaminates the electroplating solution, so that care must be taken during use. Furthermore, since the above-mentioned conventional method is basically a wet process, it is unsuitable as a method for attaching a release coating to a fine concavo-convex pattern like an optical disk stamper. Also,
The surface of the stamper for an optical disk may be contaminated by the dichromic acid solution and defects may increase.

The present invention has been made in view of the above-mentioned problems, and there is no need for waste liquid treatment, there is no environmental problem, there is no contamination of the electroplating liquid, and a stamper having high transferability and few defects can be obtained. The purpose is to provide a method of duplicating a stamper.

[0005]

In order to achieve the above object, a method of duplicating a stamper for an optical disk of the present invention uses a stamper having a peeling film made of an oxide film formed by oxygen plasma ashing treatment. Characterize.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method of copying an optical disk stamper according to the present invention will be described below with reference to FIG. Master stamper 1 made by nickel electroforming (Fig. 1
The surface of (a)) is subjected to oxygen plasma ashing treatment,
The surface of the master stamper 1 is cleaned, and a release coating 1a made of an oxide film is formed on the surface of the master stamper 1 (FIG. 1 (b)). The oxygen plasma ashing treatment of the master stamper 1 is preferably performed until the master stamper 1 is completely wet with pure water (contact angle is 5 degrees or less). If a clean optical disk stamper surface cannot be obtained only by the oxygen plasma ashing treatment, it is desirable to perform wet chemical cleaning after the oxygen plasma ashing. After oxygen plasma ashing treatment is applied to the surface of the master stamper 1, nickel electroforming is performed using the master stamper 1 as an electrode, nickel is adhered to a predetermined thickness, and then peeled off to form an uneven pattern opposite to the master stamper 1. A mother stamper 2 having is obtained (FIGS. 1C and 1D). Similar to the master stamper 1, the surface of the mother stamper 2 is subjected to oxygen plasma ashing treatment to form the release coating 2a on the mother stamper 2 (FIG. 1 (e)). Using this mother stamper 2 as an electrode,
The nickel stamper is electroformed to the specified thickness and the mother stamper 2
By peeling from the sun stamper 3 having the same concavo-convex pattern as the master stamper 1 (see FIG. 1).
(F), (g)).

As conditions for the oxygen plasma ashing treatment in the present invention, an oxygen gas pressure of 3 to 10 Pa, a high frequency voltage of 200 to 450 W, and a time of 3 to 5 minutes are preferable.
By performing oxygen plasma ashing treatment in this range, the film thickness obtained by the dichromic acid solution is almost equal to 0 / N.
A release coating having a relationship between i molar ratio and depth is obtained.

A schematic configuration diagram of the oxygen plasma ashing apparatus used in the present invention is shown in FIG. An oxygen gas was introduced into the etching tank 4, and a vacuum pump (not shown in the figure).
Is used to keep the inside of the etching tank 4 at a low pressure. When a high-frequency electric field is applied to the optical disk stamper 6 by the high-frequency voltage device 5, oxygen plasma 7 (consisting of atomic oxygen, ionic species, electrons, neutral species and the like having high chemical activity) is generated. The optical disk stamper 6 is mounted on the lower electrode portion 8 of the etching tank 4, and connects the high frequency voltage generator 5 to which the DC bias component is applied to the lower electrode portion 8.
When a high frequency voltage generator 5 applying a DC bias component is connected to the lower electrode portion 8, a voltage effect is generated on the electrode surface due to a large difference in mobility between electrons and ions, and oxygen ions are generated in this anode drop. Is the upper electrode portion 9 and the lower electrode portion 8
And, it is incident along the vertical electric field on the stamper 6 for the optical disk, and the reactive etching proceeds. Also,
Oxidation by chemically active atomic oxygen decomposes contaminants such as organic substances and forms an oxide film on the surface of the optical disk stamper. Further, when the oxygen plasma ashing treatment is applied, the amount of oxygen on the surface becomes larger than that in the case where the treatment is not applied, and the oxide is generated up to the inside, so that a peeling film necessary for duplication of the stamper for an optical disk is formed.

[0009]

As described above, according to the present invention,
Since no peeling film is provided on the stamper for optical discs using a dichromic acid solution, there is no cost for waste liquid treatment of the dichromic acid solution, there is no need to consider the effect on the environment, and electroplating is also possible. There is no contamination to the liquid. Further, in the present invention, since the release coating is provided by the oxygen plasma ashing treatment on the stamper for an optical disk having a fine concavo-convex pattern, the stamper having excellent transferability and few defects is duplicated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of copying an optical disk stamper of the present invention.

FIG. 2 is a schematic configuration diagram of an oxygen plasma ashing apparatus.

FIG. 3 is an explanatory diagram of a conventional method for manufacturing an optical disk stamper and a method for copying the same.

[Explanation of symbols]

 1 Master Stamper 2 Mother Stamper 3 Sun Stamper 1a, 2a Release film

Claims (1)

[Claims] 1. A method of duplicating a stamper for an optical disk, wherein a stamper having a peeling film made of an oxide film formed by an oxygen plasma ashing process is used.